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Microscopes & Cells
Don’t copy down this slide – just listen
Microscopes and Cells: History
• In 1663, Robert
__________
Hooke
coined the term “cells”
• 10 years later,
Anton
van Leeuwenhoek
_________________
observed bacteria and
protozoa
Browne
• In 1833, Robert
__________
observed and coined
the term “nucleus”
Guten Tag, Dr. Shwann
Cell Theory: History
Guten Tag, Dr. Schleiden
• In 1838 (and 1839)
German scientists,
Matthias Schleiden
________________
&
Theodore Schwann
________________
independently came
up with the
“Cell Theory”
It appears we have come
up with a very similar
theory…
What shall we call this
theory?
Cell Theory
1. All living things are composed of one or
more cells.
2. Cells are organisms' basic units of
structure and function.
3. Cells form by free-cell formation, similar
to the formation of crystals (spontaneous
generation).
• In 1855, German physician Rudolph
Virchow discovered that…
all cells must
come from
pre-existing
cells.
Please add the above as point #4 to the
cell theory
How big are cells?
• Eukaryotic cells include
plant
animal cells.
_______
& _______
• Most eukaryotic cells are
between 10
__ and ___
100 m.
• What is the limit of the
light microscope? 0.2 m
• Why? It is limited to the
visible light spectrum
• What is used to see
smaller objects?
__________________
Electron Microscopes
Electron Microscopy
• ___________
Transmission Electron
Microscopes (TEM)
emit light through a thin
piece of heavy metal
ion stained tissue
Scanning Electron
• ________
Microscopes (SEM)
reflect light off of a
piece of heavy metal
ion stained tissue
Prokaryotic Cells (cells without a
nucleus) for ex. bacteria
Label this diagram in your handout
DNA (Nucleoid)
Ribosomes
Plasma Membrane
Cytoplasm
Cilia
Cilium
Flagella
Flagellum
TEM of a bacterium
Eukaryotic Cells
(cells with a nucleus)
Plant cell
Animal cell
Eukaryotic cells
include both plants
and animal cells
Differences and similarities between
Prokaryotes and Eukaryotes
Differences
Prokaryotes lack:
1.True nucleus
2.Membrane bound
organelles
Prokaryotes are much
smaller than eukaryotes
(prokaryotes are
~1 – 10 m and eukaryotes
are 10 – 100 m )
Similarities
Both have:
1. DNA
2. Cytoplasm
3. Ribosomes
4. Plasma Membrane
The Plasma Membrane (1)
Carbohydrate side chains
Don’t copy down this slide – this is just review
Proteins
Hydrophilic Region
Hydrophobic Region
Hydrophilic Region
Phospholipid
TEM of a red blood cell
The Plasma Membrane
(in all cells)
Start taking notes in your table given to you in class
• It is a semi-permeable
barrier that allows for
the passage of certain
things based upon
charges and
size
______,
_______,
solubility in fat
_____________.
• What are the forms of
transport across a cell
membrane? Active and Passive Transport
Plasma Membrane’s
Microvilli
Add this to the info on plasma membrane
• Microvilli are fingerlikeprojections from the cell’s
membrane that increase
the surface area.
Cell Wall
(in plant cells and prokaryotic cells)
•
Surrounding the cell membrane , this
feature does the following for plant cells
and prokaryotes:
1. Provides Support
2. Provides Protection
Cytoplasm
(in all cells)
• The jelly-like fluid that holds all organelles
within the cell
Nucleus and
nucleolus
SEM of a freeze-fractured
nuclear membrane
(in eukaryotic cells)
• Ribosomes are
made here:
nucleolus
• DNA and
proteins form
chromatin,
found in the nucleus
• Openings in the
nuclear membrane
Nuclear pores
TEM of nuclear pores
Ribosomes: (in all cells)
Function in protein synthesis (formation)
1. Proteins made by free ribosomes stay in the cell
2. Proteins made by attached ribosomes are shipped
out of the cell or sent to the membrane
Free ribosomes
Attached ribosomes
(on ER)
TEM of ribosomes
Ribosome unit
Endoplasmic Reticulum
(in eukaryotic cells)
There are two types:
1. Rough ER has ribosomes
attached.
•
Modifies & transports
proteins
2. Smooth ER does not have
ribosomes on it.
•
•
•
Synthesizes lipids
Breaks down carbohydrates
Detoxifies drugs & poisons
Golgi Apparatus (in eukaryotic cells)
ER products move here in vesicles
It is the center of
Warehousing, Sorting and
Shipping of Proteins
Vesicles (in eukaryotic cells)
Organelles that
transport
materials
from the ER
to the golgi
and
eventually to
the plasma
membrane
Mitochondria (in eukaryotic cells)
Cellular Respiration takes place in this organelle.
It is often called the “ powerhouse “ of the cell because it
creates energy for the cell
Chloroplasts (in plant cells)
• An organelle that converts energy from the
sun into chemical energy (sugar)
The process is called:
Photosynthesis
The Cytoskeleton
(in all cells)
• A network of fibers that extend
throughout the cytoplasm,
• Three types:
Microtubules
Microfilaments
Intermediate
Filaments
Cytoskeleton: Functions
1. Provides shape and support (skeletal)
2. Moves the organelles within the cell and
helps move flagella/cilia
Organelle
Centrosome (in eukaryotic cells) and
Centrioles (in animal cells only)
• Centrosomes make microtubules.
• In animal cells, a pair of structures called
centrioles (made of microtubules) help in
cell division.
centrosome
centrioles
Cilia and Flagella
(in all cells)
• Hair-like projections that
aide in movement
• Cilia are shorter,
more numerous and
move back & forth
• Flagella are longer &
move in a snake-like
motion.
Lysosomes (in animal cells)
• Membrane-bound
engulfing a
organelle in animal cells Lysosome
worn-out organelle
that contains
digestive
___________enzymes
that help clean-up the cell
Vacuoles (in eukaryotic cells)
• Large, central
organelle in plants
• Stores water and
waste products
• In animals, it stores
food and is small in
size compared to
plant vacuoles